BEACH, a word of unknown origin; probably an old dialect word meaning shingle, hence the place covered by shingle. Beach sometimes denotes material thrown up by waves, sometimes the long resulting ridge—though this generally has the special term of "storm beach"—but usually denotes the area between high and low water, or even the area between land and sea covered with material thrown up by storms.
The actual character of beach material depends upon the rocks inshore or the boulders deposited on the shore as a result of past glaciation, currents and waves. The Isle of Wight ends westward in the well-known "Needles" consisting of chalk with flints. Dis integration of this rock separates the finer chalk, carried seawards in suspension, from the hard flint, piled as rough shingle. Currents sweep constantly eastward up channel, and the rough flint shingle is rolled along toward the Ventnor rampart, and ground finer and finer, until it arrives as a very fine flinty gravel at Ventnor pier. Sandown Bay follows with cliffs composed mainly of greensand, and here the beach at low water is sandy and smooth. The eastern end of the island is again composed of chalk with flints, and here the beach material as at the western end consists of very coarse flint shingle. In this, as in similar cases, the material has been dragged seawards from the land by constant action of the under tow that accompanies each retreating tide and each returning wave. The grading of material is also excellently shown in Chesil bank where the pebbles in various sections are remarkably uniform in size and shape. The resulting accumulated ridge is battered by every storm, and thrown above ordinary high water mark in a ridge ; an older example is the long grass-grown mound that has blocked the old channel of the Yar and diverted its waters into Yaverland Bay. Sandown furnishes an instructive example of the power of the eastward currents with their high-storm waves. The groins built to preserve the foreshore are piled to the top with coarse pebble and shingle on the western side, while there is a drop of over 8ft. on to the sands east of the wall. The force of the waves has been estimated on the west coast of Scotland and found to be as much as 3 tons per square foot. Against these forces the preservation of the shore from the advance of the sea becomes an extremely difficult undertaking. The beach advances in front of the encroaching sea, burying former beaches under the sand and mud of the now deeper water, or it retreats when the sea is with drawn from the land or the land rises locally, leaving the old shingle stranded in a "raised beach."